"""passbook flow signals"""
from django.core.cache import cache
from django.db.models.signals import post_save
from django.dispatch import receiver
from structlog import get_logger
LOGGER = get_logger()
def delete_cache_prefix(prefix: str) -> int:
"""Delete keys prefixed with `prefix` and return count of deleted keys."""
keys = cache.keys(prefix)
cache.delete_many(keys)
return len(keys)
@receiver(post_save)
# pylint: disable=unused-argument
def invalidate_flow_cache(sender, instance, **_):
"""Invalidate flow cache when flow is updated"""
from passbook.flows.models import Flow, FlowStageBinding, Stage
from passbook.flows.planner import cache_key
if isinstance(instance, Flow):
total = delete_cache_prefix(f"{cache_key(instance)}*")
LOGGER.debug("Invalidating Flow cache", flow=instance, len=total)
if isinstance(instance, FlowStageBinding):
total = delete_cache_prefix(f"{cache_key(instance.target)}*")
LOGGER.debug(
"Invalidating Flow cache from FlowStageBinding", binding=instance, len=total
)
if isinstance(instance, Stage):
total = 0
for binding in FlowStageBinding.objects.filter(stage=instance):
prefix = cache_key(binding.target)
total += delete_cache_prefix(f"{prefix}*")
LOGGER.debug("Invalidating Flow cache from Stage", stage=instance, len=total)
